To sufficiently decrease the amt. of residual C even if the compacts which can be treated at one time is increased and to efficiently produce the high-quality sintered compacts by alternately repeating a reducing gaseous atmosphere and a vacuum atmosphere during the course of a heating stage to sintering, then sintering the compacts in the reducing atmosphere.
The carbon component gases generated simultaneously with the occurrence of a decarburization reaction by a reducing gas at the time of heating for the purpose of sintering are removed outside the furnace at the time of the vacuum atmosphere and in succession, the decarburization reaction progresses smoothly and rapidly in the reducing gaseous atmosphere. The decarburization is efficiently and surely executed and the high-quality sintered compacts are obtd. by repeating such operation. Consequently, the treatment, of a large amt. of the compacts at one time is made possible by ensuring of the decarburization. The repetition of the atmospheres is preferably executed in a temp. region where the decarburization reaction starts and the reaction progresses sufficiently. The temp. region is preferably set at 800 to 1000°C.
IMASHITA KIYOTAKA
MADARAME HIROKAZU
ENDO YASUO
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